Bad render of first frame of every clip ( nested timelines )

Hi All,

I've been experiencing a really annoying issue. Renders (no matter the codec) have some clips (when it happens, always the first frame) with weird grading (darker) look.

Attached above are 3 frames of the problem: First frame (at the top) is the very last rendered frame of a given clip; 2nd (middle) is the very first rendered of the next that comes next; and the third (bottom) is the the second rendered frame of that same clip. Notice only the first frames gets bad rendering. This happens no matter the codec.

Here are some facts of my workflow.

- Film (feature) has N scenes, where every scene is a timeline itself, name "S001", "S002", and so on
- a master time (named "FULL") line uses all the timelines (the scenes) as embedded "clips" (I'll call them here as "sub-timelines"). So total I have N+1 timelines in the project.
- my grades are done ONLY inside the scenes (S001, S002, l..), at levels clip , pre and post-clip group
- I use ACEStt worflow for flexibility purposes. Input is BM film 4k , output is REC709
- Footage is 100% BM cinemaDNG raw

Here are some of the symptoms. As I already mentioned, renders in any codec get the first frames of many clips completely messed in terms of grading. Also, when I am in the edit page, editing timeline "FULL", and when I position the cursor ramdomly at anypoint over a sub-timeline , my viewer gets the same weird look. Clicking the the viewer, or simple moving the playback cursor left or right (with the arrow keys) sort of "refreshes" the viewer and it looks normal again. It's just the the pipeline of grading doesnt "wake up" when I position the playback cursor onto these sub-timelines.

I tried lots of stuff. Changing to Davinci ACES, Acesstt, export and restore the whole project, comple wipe all render caches and optimized media, removing post and pre group gradings, nothing seems to work. (update, moving to DAvincy YRBG makes the problem disappear, but of course, after having graded everything in ACES, it just look terrible, so this is not an option at this point)

Im starting to suspect this is related to a combination of ACES + nested timeline workflows. Unfortunately logs dont show anything remotely related to the problem.

Anyone experiencing the same issue ?

Thanks in advance


keywords : "nested timeline" "aces" "first frame"
Windows 10 64Bits, 16G RAM, 6T + 6T + 512G (ssd) as boot drive
Davinci resolve studio 12.5.4.0.19
Nvidia 1070 8G
BM DeckLink mini monitor 4K
Eizo Monitor 247x

Update : Another symptom I notice today. When I am in the master level timeline, color tab, several clip thumbnails (each one referring to a sub-timeline) shows the same weird look. right clicking and "update all thumbnails" fix them. The renders continue to show these weird first frames... My next attempt is to decompose the sub-timelines into the master timeline (will become a VERY polluted time time) and see if this persists.

Update : I am inclined to say that the problem is really something related to ACES *only*. After converted all the sub-timelines into compound clips and the problem persists.

Update : I converted (after a lot of pain) the whole project to Davinci YRGB and the problem is completely gone even using sub-timelines or compounded clips. Im confident to say this is a bug in the ACES workflow, when using some form of nested content. Too bad cause I really love it

[Peter Chamberlain]

Please see
viewtopic.php?f=21&t=54509